There could be a number of different reasons. The following discusses a few of the most common ones.
All the calculations done by the ChildView® software, with the exception of the Child Support Guideline table look up, are time sensitive. ChildView® uses the most current information at the time of a specific version release if the current year is chosen. For example, version 2021.1.0 incorporates all the federal, provincial and territorial income tax changes that are effective for January 1, 2021. This includes not only the standard changes due to indexation but also the relevant changes that have been announced in the federal, provincial and territorial budgets prior to the version release date. Changes announced after a version release date are incorporated into the next release, the timing of which will depend on the magnitude of the changes. Because ChildView® issues regular updates, mid-year tax changes are addressed in a timely manner. Updates are usually issued in the late winter or early spring to incorporate CPP, EI and income tax changes, and in early summer to incorporate the benefits changes (CCB, GST and provincial / territorial programs).
Benefits programs are administered by governments on a July to June cycle, not on the calendar year cycle of income tax. ChildView®'s calendar year calculation includes blended benefits comprised of the January to June and July to December cycles, while the July forward calculation reflects the benefits changes that are effective July 1 of that year. In addition, the ChildView® program allows you to choose whether to use the "base taxation year" incomes or the current year income when doing the benefits calculations.
Further, calculated results are dependent on the assumptions that go into the calculations. Different assumptions produce different results. For example, different results might be obtained where one calculation assumes that the recipient is a single parent and the other reflects the fact that the recipient is living in a common-law relationship. Through the detailed reporting available in the software, ChildView® makes the assumptions used in the calculations transparent.
While ChildView® cannot comment on what other calculators may or may not be doing, if you require verification or explanation of specific numbers, we are happy to provide you with complete details. Also, in the print preview of the ChildView® cashflow report (Shedule D) clicking on a number highlighted in blue will allow you to drill down to greater detail, such as the composition of the benefits number. This feature is also available in all the spousal support reports as well.